Dump wagon hoist



April 9, 1963 I. w. KLEIN 3,084,908

DUMP WAGON HOIST Filed Feb. 1, 1960 2 Sheets-Sheet 1 ATTORNEYS.

April 9, 1963 I. w. KLEIN 3,084,908

DUMP WAGON HOIST Filed Feb. 1, 1960 2 Sheets-Sheet 2 ATTORNEYS.

United States Patent Dakota Filed Feb. 1, 1960, Ser. No. 6,023

7 Claims. ((33. 254-3) This invention relates to a hydraulic hoist for dump wagons and the like, and comprises a jack-knife unit including hydraulically-operated means for moving two pivots of the unit relatively apart.

One object of the invention is to provide a jack-knife unit that has one of its two pivots operatively connected to the front bolster of a wagon that includes a wagon box pivoted to the rear bolster thereof, and its other pivot operatively connected to the front end of the box for thereby elevating such front end by operation of the hydraulically-operated means to discharge the contents of the box.

Another object is to provide a unit of the character referred to in which substantially the same hydraulic working pressure is required throughout the entire range of its movement as a result of a novel mechanical construction including a rolling fulcrum connection between the hydraulically-operated means and one arm of the jack-knife unit. I I

Still another object is to provide a curved track and roller arrangement as a connecting means between a hydraulically-operated means and a lever of the jack-knife unit which maintains a fixed fulcrum connected to such lever for about half of the jack-knifing movement, and a gradual shifting of the fulcrum thereafter during further jack-knifing movement to secure maximum opening of the jack-knife, unit without the pivotal connection of the hydraulically-operated means approaching and/ or passing over center with respect to the pivot between the two levers of the jack-knife, the arrangement providing a gradual leverage change to maintain a substantially constant working pressure requirement for the hydraulic fluid supplied to the unit.

A further object is to provide a jack-knife unit comprising two jack-knife levers pivoted together and having their extremities initially located adjacent each other, in combination with hydraulically-operated means comprising a cylinder and piston forming an extensible connection between one of such extremities and a variable or shiftable pivot of the other jack-knife lever.

Still a further object is to provide a jack-knife lever arrangement with the extremities constituting first and third pivots, the pivotal connection of the levers together consituting a second pivot and the shiftable pivot constituting a fourth pivot movable along a curve and normally laterally spaced fromthe second pivot so that at first the fourth pivot swings toward a position of alignment :between the first and second pivots but before reaching such position the axis of the hydraulically-operated unit becomes coincident with the center about which the curve is formed as a radius, which radius is considerably shorter than the distance at any position between the first and fourth pivots, whereupon further extension of the hydraulically-operated unit effects a rolling fulcrum action of the fourth pivot along the curve with the axis of the hydraulically-operated unit remaining substantially coincident with said center until the other end of the curve is reached by the fourth pivot and remains there during any further opening movement of the jack-knife unit, whereby the shifting of the fourth pivot relative to the second jack-knife lever delays the approach of such axis toward the second pivot during the rolling fulcrum action.

An additional object is to provide a jackaknife lever and extensible hydraulic unit combination in which required hydraulic operating pressures are maintained at minimum value throughout the entire range of jackknifing movement in accordance with variable loading because of changing load attitude, the desired results being obtained by a rolling fulcrum connection that effects a gradual shift of leverage.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my hoist, whereby the objects above contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in detail on the accompanying drawings, wherein:

FIG. 1 is a side elevation of a' dump wagon and my dump wagon hoist or jack-knife unit mounted thereon, the unit'being opened a little more than three-fourths of its extent;

FIG. 2 is a front elevation of my jack-knife unit as on the indicated line 22 of FIG. 1;

FIG. 3 is a side elevation of my jack-knife unit or dump wagon hoist in the starting position; and

FIGS. 4, 5, 6 and 7 are diagrammatic views showing respectively positions wherein the jack-knife unit is about one-half open in FIG. 4, about the same position as FIG. 1 in FIG. 5, nearly nine-tenths open in FIG. 6, and fully open in FIG. 7.

On the accompanying drawings I have used the reference numeral 10 to indicate in general the chassis of a dump wagon; 12 and 14 the rear and front bolsters thereof; 16 and 18 the front and rear wheels thereof; 20 the tongue thereof; 22 the dump wagon box thereof; and 24 the underframing of the box 22. The box 22 is hinged to the rear bolster 12 as shown at 15. Dump wagons of this character are now in general use on farms for hauling grain and dumping the grain as at 21 into a hopper 23 of a grain elevator 25 which delivers it to the granary, the rear end gate of the box 22 of course being removed or at least raised to permit outflow of the grain 21.

Heretofore, various types of hoist units, some hydraulically operated, have been utilized as a means to elevate the front end of the box 22 as shown in FIG. 1 to effect the outflow of grain as indicated at 21. Some of these units have been mere cylinder and piston arrangements to form an extensible unit connected between the chassis 1t) and the underfrarning 24, and others have been provided with various leverage arrangements to change the leverage advantage during the extent of movement of the unit to secure substantially equal hydraulic pressure throughout the range of operation of the hoist. Some of the prior devices have also been jack-knife units and the herein disclosed hoist is of that general character,

but has a simplified arrangement involving but very few and simple parts to accomplish the desired change in leverage by a rolling fulcrum action.

My jack-knife unit comprises a first pivot P in the [form of a steel rod or tube which may be pivoted to the front bolster '14 of the chassis 10 by means of a pair of brackets 28. A pair of tubular arms 30 have their front ends welded to the pivot P and form a first lever L of a jack-knife lever arrangement, the second lever of which is shown at L The levers L and L are pivotally connected together by a second pivot P comprising a rod or shaft welded to the rear ends of the arms 30 and pivotally connected to the lever L The lever L is of channel shape as shown in FIG. 2 having upper flanges 34, side plates 34* and inturned reinforcing flanges 34, the pivot P? being journalled in the side plates 34*.

The second jack-knife lever L terminates in a third pivot P formed of -a steel tube welded to the side plates 34*, and this tube is pivotally connected to the underframing 24 of the dump wagon box 22 by rotatably sur- 3 rounding a tube 37 having its ends welded to brackets 38 that are bolted or otherwise suitably secured to the underframing 24.

For opening the jack-knife L -L I provide hydraulically-operated means comprising a cylinder 42 having a piston 46 therein to which is connected a piston rod 48 that extends from one end of the cylinder and terminates in a stub shaft 50 on which a pair of fulcrum rollers 52 are rotatable. The axis of the rollers 52 constitute a fourth pivot P of special characteristics as will hereinafter appear.

A reinforcing angle 40 is welded between the arms 30 and forms a pivot seat for the left-hand end of the cylinder 42 as shown in FIG. 3, a stop flange 44 being welded to the end of the cylinder and resting by gravity acting on the hydraulically-operated means to keep the flange 44 seated on the angle 4b. The pivoting action between the pivot seat formed by the flange 44 and the angle 40 is closely adjacent the pivot P and for all practical purposes is substantially thesame and will therefore not be referred to separately.

The fourth pivot P is shiftable relative to the second jack-knife lever L by reason of being normally seated at one end of a curved track 56 as shown in FIG. 3, flanges 54 being provided in opposition to the track 56 to keep the fulcrum rollers 52 in position. The curvature for the track 56 is about a center point indicated at 58, and the curved track 56 confines the fourth pivot P along a path indicated as 50 likewise on an effective radius R from the point 58. The radius R, it will be noted, is substantially less than the distance from the first pivot P to the fourth pivot P of FIG. 3, the purpose of which will hereinafter appear.

Practical Operation In the operation of my jack knife unit when it serves as a dump wagon hoist, the parts are initially in the position shown in FIG. 3 with the first and third pivots P and F spaced apart an extension distance E hydraulically-operated means 42-43 is extended by introduction of hydraulic fluid under pressure into an inlet 43 of the cylinder 46 (see FIG. 3), the distance between the first and third pivots increases as shown in FIGS. 4, 5, 6 and 7 by the extension distances E E E and E respectively.

First of all, the fourth pivot P is at the right-hand end of the curved track 56 as shown in FIG. 3 and remains in that position until the parts are in the diagrammed position of FIG. 4 with the axis of the hydraulicallyoperated means (or center of the piston rod 48) passing through the center 58 for the effective radius R of the curved path 50 Thereafter any further extension of the hydraulically-operated unit will cause a shifting of the fourth pivot P along the curved track 56 as shown, for example, in FIGS. 5 and 6. In FIG. 5 the rolling fulcrum or pivot P is about half way of the track 56, whereas in FIG. 6 it has arrived at the left-hand end of the track. All during the operation just described the axis of extension of the hydraulically-operated means (represented by the rod 48 in FIGS. 4, 5 and 6) will pass through the center 58 as depicted because of the track 56 being curved from that center and its radius being relatively short as compared to the distance at any position from P to P Thereafter, upon further extension of the hydraulicallyoperated means 42-4-8 as to the position shown in FIG. 7, the rolling fulcrum, or fourth pivot P, will remain at the end of the curved track 56 that is uppermost. Thus when the position of FIG. 4 is reached and the axis of the hydraulically operated means is approaching the second pivot P and losing leverage, the leverage is gradually increased by the fourth pivot P shifting through the rolling fulcrum action described until the maximum leverage (or distance of pivot P from pivot P is reached as in FIG. 6, whereupon the final fulcrum position is maintained during further extension of the hydraulically-operated As the unit. During this operation, however, the wagon box is gradually being tilted to a position where it imposes less weight on the jack-knifing unit, and the contents of the box are being discharged, so that the leverage that was required to start the load toward dumping position is no longer necessary. The rolling fulcrum action thus levels out the hydraulic pressure requirements of the hydraulically-operated means but with a gradual shift of leverage between the FIG. 4 position and the FIG. 6 position after which the box is in such an elevated position that reduced leverage can be tolerated and occurs by movement of the piston rod 48 below the center 58 as shown in FIG. 7 and toward dead-center position with respect to the second pivot P In FIGS. 4 to 7 inclusive I have not attempted to show the change in attitude of the entire unit but only the second jack-knife lever L relative to the first lever L but reference to FIG. 1, wherein the FIG. 5 position is shown, makes it-obvious how the operation occurs. The main consideration of course is that the third pivot P is moving away from the first pivot P as indicated by E to E for elevating the front end of the box 22.

From the foregoing specification it will be obvious that I have provided a jack-knifing type of dump wagon hoist unit consisting of very few and simple parts that are operatively connected together in a simple manner and operate to provide an initial jack-knifing movement without pivot shift, then a gradual pivot shift by a rolling fulcrum action followed by further movement if desired without further rolling fulcrum action. The device thus enables the provision of a gradually shifting fulcrum as distinguished from those types of fulcrums that are sudden shifts from one leverage to another, and altogether provides a very smooth hoisting operation for a dump wagon or the like.

Some changes may be made in the construction and arrangement of the parts of my dump wagon hoist without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claim any modified forms of structure or use of mechanical equivalents which may reasonably be included within their scope.

I claim as my invention:

1. In a dump wagon hoist, a jack-knife unit comprising a pair of jack-knife levers having at one end a first pivot, a second pivot between the levers and a third pivot at the other end, extensible hydraulical means interposed between said first pivot and an operative connection to one of said jack-knife levers, said operative connection comprising a rolling fulcrum consisting of a roller carried by said extensible hydraulic means and a curved track carried by said one of said jack-knife levers and of less radius than the distance between said first pivot and said operative connection, with said roller located at the end of said curved track closest to said second pivot by reason of the other end thereof extending toward said first pivot when said jack-knife levers are in their initial closed position whereby said rolling fulcnum remains at said end of said curved track closest to said second pivot as said bydraulically-operated means is extended until the center from which said curved track is generated becomes coincident with the axis of said hydraulically-operated means, and further extension of said hydraulically-operated rneans thereafter effecting gradual free rolling of said roller along said curved track toward said other end thereof.

2. In a dump wagon hoist, a jack-knife unit comprising a pair of jack-knife levers having at one end a first pivot, a second pivot between the levers and a third pivot at the other end, extensible hydraulic means interposed between said first pivot and 18.11 operative connection to one of said jack-knife levers, said opera-tive connection comprising a rolling fulcrum consisting of a roller carried by said means and a curved track carried by said one of said jack-knife levers and of less radius than the distance between said first pivot and said roller, with said roller located at the end of said curved tnack closest to said sec- 0nd pivot by reason of the other end thereof extending toward said first pivot when said jack-knife levers are in their initial closed position whereby said rolling fulcrum remains at said end of said curved track closest to said second pivot as said hydraulically-operated means is extended until the center from which said curved track is generated becomes coincident with the axis of said hydraulically-operated means, further extension of said bydraulically-operated means thereafter effecting gradual free rolling of said roller along said curved track toward said other end thereof, and still further extension of said hydraulically-operated means after said roller reaches said other end being effected with said other end as a fourth pivot between said hydraulically-operated means and said one of said jack-knife levers with said fourth pivot fixed relative to the latter.

3. In a dump wagon hoist, a pair of jack-knife levers pivoted together at a pivot point to form a jack-knife lever unit and having operative ends adapted to be extended in relation to each other, and an extensible unit for effecting such extension interposed between one end of said jackknife lever unit and operatively connected at its other end to one lever of the unit, said operative connection comprising a curved track and a roller movable therealong and carried by the extending end of said extensible unit to effect first a pivoting action between said extensible unit and said one lever at the end of said curved track closest to the pivot point of said levers, and then a gradual free rolling of said roller along said track to the other end thereof as said extensible unit is progressively extended.

4. A dump wagon hoist of the character disclosed comprising a pair of jack-knife levers pivoted together at a pivot point to form a jack-knife lever unit and having operative ends adapted to recede from each other, and hydraulically-operated means for effecting such recession comprising an extensible unit interposed between one end of said jack-knife lever unit and operatively connected at its other end to one lever of the unit, said operative connection comprising a curved track carried by said one lever and a roller movable therealong and carried by the extending end of said hydraulically-operated means to effect first a pivoting action bet-ween said hydraulic-allyoperated means and said one lever at the end of said curved track adjacent the pivot .point of said levers and then a gradual free rolling of said roller along said track to the other end thereof, the center for the curve of said track being adjacent a line connecting said pivot point to the operative end of said one lever, and the opposite end of said curved track extending toward said last mentioned operative end.

5. In a dump wagon hoist of the character disclosed, a jack-knife lever unit comprising a pair of jack-knife levers pivoted together at a pivot point and having operative ends adapted to be extended in relation to each other, and hydraulically-operated means for effecting such extension, said means being interposed between the operative end of one of said jack-knife levers of said unit and operatively connected at its other end to the other lever of said unit, said operative connection comprising a curved track on said other lever and a roller freely movable therealong and carried by the extending end of said hydraulically operated means in which the curvature of the track is less than the distance at any time from said operative connection to said operative end of said one of said levers to effect first a pivoting action between said hydraulicallyoperated means and said other lever at the far end of said curved track, then a gradual rolling of said roller therealong to the other end of said track and thereafter a pivoting action at said other end of said track, said track being curved away from the pivot point of said levers and having one end spaced laterally from a line between said pivot point and the operative end of said other lever, and its other end extending toward said last mentioned operative end.

6. A dump wagon hoist comprising a jack-knife unit comprising a pair of normally horizontally disposed jackknife levers having at one end of said unit a first pivot, a second pivot between the levers and a third pivot at the other end of said unit, extensible hydraulic means interposed between said first pivot and an operative connection to one of said jack-knife levers, said operative connection comprising a free-rolling fulcrum consisting of a curved track carried by said one of said jack-knife levers and a roller for cooperation therewith only and carried directly by the extensible end of said extensible hydraulic means, said curved track having one end thereof above said second pivot when said levers are in normal position, arched away from said second pivot and extending toward said third pivot, said roller being located at said one end when the jack-knife is closed, remaining there during the first part of the opening movement, and rolling freely and progressively along said curved track during the last part of said movement.

7. 'In a dump wagon hoist, a pair of jack-knife levers, a pivot for pivoting the levers together, said levers having operative ends adapted to be extended and recessed in relation to each other, said levers being horizontally disposed when the jack-knife is closed, and hydraulicallyoperative means for effecting such extension or recession comprising an extensible unit, a roller carried by the outer end thereof, a track carried by one of said levers, said track being curved and having one end above said pivot when the jack-knife is closed, at which time said roller is at said one end of the track, and having its other end extending away from said pivot and toward the operative end of said one lever, the curve on said track being away from said pivot, and said roller being freely movable progressively along said track during approximately the last half of the extension of said extensible unit after initial pivotable coaction with said one end during approximately the first half of said extension.

References Cited in the file of this patent UNITED STATES PATENTS 2,373,848 Owens Apr. 17, 1945 2,698,199 Godberson Dec. 28, 1954 2,706,102 Cresci Apr. 12, 1955 2,793,767 Smith et al May 28, 1957 2,928,558 Bamford et a1. Mar. 15, 1960 

3. IN A DUMP WAGON HOIST, A PAIR OF JACK-KNIFE LEVERS PIVOTED TOGETHER AT A PIVOT POINT TO FORM A JACK-KNIFE LEVER UNIT AND HAVING OPERATIVE ENDS ADAPTED TO BE EXTENDED IN RELATION TO EACH OTHER, AND AN EXTENSIBLE UNIT FOR EFFECTING SUCH EXTENSION INTERPOSED BETWEEN ONE END OF SAID JACKKNIFE LEVER UNIT AND OPERATIVELY CONNECTED AT ITS OTHER END TO ONE LEVER OF THE UNIT, SAID OPERATIVE CONNECTION COMPRISING A CURVED TRACK AND A ROLLER MOVABLE THEREALONG AND CARRIED BY THE EXTENDING END OF SAID EXTENSIBLE UNIT TO EFFECT FIRST A PIVOTING ACTION BETWEEN SAID EXTENSIBLE UNIT AND SAID ONE LEVER AT THE END OF SAID CURVED TRACK CLOSEST TO THE PIVOT POINT OF SAID LEVERS, AND THEN A GRADUAL FREE ROLLING OF SAID ROLLER ALONG SAID TRACK TO THE OTHER END THEREOF AS SAID EXTENSIBLE UNIT IS PROGRESSIVELY EXTENDED. 